Relay



Sept. 20, 1938. v

c. s. KNOWLTON'ET AL RELAY Filed April 17, 1936 INVENTORS HMSPICER ATTORNEY Patented Sept. 20, 1938 [UNITED STATES PATENT OFFICE RELAY (flarcnee S. Knowlton, Springfield, and Hobart 1!.

Splcer, Bidgewood, N. 1., asaiznors to Bell Telephone Laboratorlcs, Incorporated, New York, N. Ya, a corporation of New York Application April 17, 1936, Serial No. 74,916

.7 Claims. (Cl. 200-97) This invention relates to a time delay relay or circuit controlling device. The object of the invention is to provide a relay, the contacts of which may be opened or closed an appreciable 5 interval after the energization of the relay winding.

It is often desirable in electrical systems to provide for delaying the closing or opening or a circuit for an appreciable interval, for example of several seconds or minutes after the establishment of another circuit or to make and break a circuit periodically at a slow predetermined rate.

In accordance with the present invention a relay having the desired characteristic of delaying the operation of its contacts for a considerable interval after its winding is energized is provided which comprises an electromagnetic field surrounding an envelope within which is a pool of mercury or other fluid having similar characteristics. A n annular displacer or core of magnetic material is positioned within the envelope, floated on the mercury pool, and subject to the magnetic field. Centrally positioned in the envelope and inside the annular core is a giass tube partly submerged in the pool of mercury. This tube is closed with the exception of an open ing near its base and a restricted vent in its upper end. Extending from outside the envelope into the tube and sealed to both the envelope and tube are two contacts electrically insulated from each other. A float member having a conducting surface is positioned in the tube and subject to the rise and fall of the mercury in the tube for bridging the contacts. This float member may 5' be arranged to normally bridge the-contacts and to open the circuit between them when the mercury rises in the tube and lifts the float, or may be arranged to bridge normally open contacts when the mercury rises in the tube, as may be desired.

If the relay is of such a character that the float normally closes the contacts with the magnetic field unenergized, the core floats on the pool of mercury and the level of the pool is such that 45' the float is unaffected thereby. When the field is energized, however, the coreis submerged in to the mercury pool raising the level of the pool so that mercury is displaced through the opening in the lower end of the tube and raises the 55 the operating time of the relay may be deterfloat thereby opening the circuit between the mined. When the magnetic circuit is deenergized the core rises quickly and the level of the mercury drops at once thereby again bridging the contacts.

Should it be desired to delay the closure of normally open contacts the relay could be constructed in the same general manner except that the contacts would be positioned above the float and would be closed only after the float has been lifted by the rising column of mercury in the tube.

For a clearer understanding of the invention reference may be had to the following detailed description taken in connection with the accompanying drawing of which:

Fig. 1 is a vertical section through the relay showing the relay in its unoperated condition with its contacts closed;

Fig. 2 is a top plan View of the relay;

Fig. 3 is a section similar to Fig. 1 with the magnet yoke and winding omitted showing the relay in its operated condition with its contacts 1 1;

Fig. 4 is a perspective view of the displaces or core of the relay;

Fig. is a perspective view of the float and upper ends of the contacts of the relay shown Fig. 1; and

Fig. 6 is a sectional view of a relay similar to Fig. 2 but modified to enable the closure of nor mally open contacts when the relay winding is energized.

In the several figures Ill designates a glass envelope in the form of a cylinder sealed oif at H and having a thickened base it. Centrally positioned within the envelope is a second glass tube l3 having a thickened base l4 and provided at its upper end with a restricted vent 15. This vent is made very minute for the purpose oi. restricting the flow of gas from the tube into the envelope. A small opening I8 is also provided in the side wall of the tube l3 for apurpose to be later described.

As disclosed in Figs. 2. and 2 two terminal wires l1 and I8 extend upwardly through the base E2 of the envelope Hi and through the base it of the tube l3 and terminate in arcuate contact portions i9 and 20 extending at right angles therefrom. The terminal wire I! is sealed into the bases of the envelope and tube and the terminal 0 ,wire It! extends through a glass sleeve 2| which and it also serve-to rigidly support the tube i3 within the envelope.

verti such that to te the tube is positioned in the lot.

the envelope ill and a second spring tinned the upper end oi the envelope, these springs being of non-magnetic material and serving to protect the envelope against shock in shipping and handling. The lower spring 2% may be suitably anchored to the base ii? of the envelope to prevent it from floating upwardly in the mercury although anchoring is not necessary since no harm would be done if it should float upwardly into engagement with the lower edge or" the core A host member 21 is provided within the tube l3 having a disc-shaped head 23 provided with teeth 29 for guiding the float in its vertical movement within the tube. These teeth are of small contact area for the purpose of reducing to a minimum the frictional contact thereof with the inside wall of tube i3 and to permit the free flow of gas past the edge of the head. The float is made of metal having good conductivity, tungsten being suitable for the purpose. Normally it rests upon the contact portions l9 and 20 or the terminal wires l1 and i8 thereby establishing a conducting bridge therebetween. In. this position its lower end is out of contact with the upper surface of the mercury pool. For insuring a good contact with the contact portions l9 and 20 a light coiled spring is inserted between the upper face of the head 28 of the float and the upper end of the tube [3. The spring 30 also serves to hold the float 21 in position to prevent damage to the tube l3 during shipping and handling.

After the assembly of the elements above described within the envelope Ill and the insertion of the mercury pool and before the upper end of the envelope is sealed oil at H, the envelope is evacuated and charged with an inert gas, such as helium, argon, hydrogen or the like.

The envelope I0 is fitted loosely within two metal sleeves 3i and 32 preferably of magnetic material and held in position bythe friction of a coil spring 33 wrapped closely around the envelope and bearing against the adjacent ends of the sleeves. This spring is of non-magnetic material such as phosphor bronze. The sleevesii and 32 are clamped by clips 35 and 35 to a laminated yoke 36 of soft iron or other suitable magnetic material. Bolts 31 serve to fasten the clips to the yoke and to clamp the laminations of the yoke together. Other bolts 38 pass through the yoke and serve to further clamp the laminations of the yoke together and to secure mounting brackets 39 to the yoke.

arao eee solenoid coil it is wound on an insulating spool iii which surrounds the magnetic sleeves 3i and between the arms or the yoke 35. As disl the operating circuit for cell 4|] extends irons one terminal of a source of electrh energy ti o coil, over terminal wire it? th' that portio Llil the eof, bridging ormaliy closed contacts, the relay r. 63 is arrange to close normally open contacts. For purpose the terminal wires 42 and are extended downwardly through the up per ends 01. the envelope l0 and tube l3 and termina e in horizontal arcuate contact portions 44 and id positioned above the float member 45. These terminal wires are sealed into the envelope and tube and serve as supports for the tube. The float $8 is similar to the float 21 disclosed in Fig. 5 and establishes a bridge across the contact portions 44 and 45 when it is floated upwardly in the tube I3 by the mercury.

It will be assumed that the relay is connected as disclosed in Fig. 1 for interrupting its own operating circuit and that it is in its normal condition with the core 23 floating on the mercury, the level of the pool of mercury extending just below the opening IS in the tube I3 and the float member 2? resting on the contact portions of the terminal wires i1 and Hi. If now electrical energy is applied to the relay the coil will become energized and will draw the core 23 downwardly into the pool of mercury until it assumes the position shown in Fig. 3. As the core moves downwardly it will displace mercury which will rise in the envelope. Some of the mercury will flow through the opening lb of tube 13 until when it rises above the upper edge of the opening IS the tube I3 will be sealed except for the restricted vent IS in its upper end.

The mercury which has been displaced by the core 23 will continue to seek a stable level by continuing to rise in the tube H! but the rate at which it is permitted to flow into the tube will now be delayed by the pressure of the gas trapped in the tube. However, as the gas escapes slowly through the vent IS the mercury level in the tube will slowly rise until it engages and lifts the float member 2'! against the tension of spring 30. When the mercury level has risen sufliciently the float member will be raised until its head portion 28 is disengaged from the contact portions i9 and 20 of the terminal wires thereby opening the circuit through the coil 40 as disclosed in Fig. 2.

Tbs coil 46 now being deenergized the core 23 will at once float upwardly in the mercury and the mercury level will drop in the envelope iii permitting the mercury in the tube I3 to flow out of the tube through the opening l6 thereby lowering the float member 21 until its discshaped head 2! is again forced into engagement with the contact portions of the terminal wires by the spring 30. The circuit through the coil 7 40 will again be made and the relay will thus intermittently operate at a predetermined rate so long as it is connected to the source oi enay- To prevent mercury vapor formed by the making and breaking of the relay contacts from ris- 19 ing and collecting in the upper end of the tube It about the vent it, which might cause a variation in the flow of gas through the vent and thus cause a variance in the delay period oi the relay, a' small quantity of asbestos fiber, felt, 18 steel wool or the like I1 is packed lightly in the upper end of the tube which will intercept the 7 particles of mercury vapor and preserve the.

normal gas flow.

The modifled form of relay disclosed in part U in Fig. 6 functions in a similar manner. When the core II is depressed into the mercury pool 22 by the energization of the relay coil, mercury is displaced and its level rises in the envelope, a part 01' the mercury flowing through the open 28 ing it in the tube i3. As the level of the mercury continues to rise in the tube It as permitted by the escape of trapped gas through the restricted vent 15, the float member 46 is raised until it engages and bridges the contact pora tions l4 and I5 oi the terminal wires 42 and 43. When the relay coil is deenergized the core 28 at once floats upwardly in the mercury and the mercury level drops in the envelope iii permitting the mercury in the tube l3 to flow out 35 through the opening i6 thereby lowering the float member 46 and opening the bridge across the contact portions of the terminal wires. It will be obvious from the disclosure that the length of the time delay when breaking or mak- 40 ing an electrical circuit may be varied within limits by increasing or reducing the size of the vent i5.

What is claimed is: 1. In a relay, a sealed envelope, a solenoid 46 coil, a pool of fluid in said envelope, an annular core within said envelope and floated on said -fluld, a tube supported in said envelope having an opening communicating with said pool of fluid and a restricted vent in the upper end thereof, 50 a pair of terminals extending into said tube and insulated from each other, and a float in said tube for bridging said terminals and operable when the fluid rises in said tube in response to the submersion oi said core in said fluid upon 55 the energization of said coil.

2. In a relay, a sealed envelope, a solenoid coil, a pool of mercury in said envelope, an annular core within said envelope and floated on said mercury, a tube supported in said envelope hav-. 60 ing an opening communicating with said pool of mercury and a restricted vent in the upper end thereof, a pair of terminals extending into said tube and insulated from each other, and a float in said tube for bridging said terminals and op- 66 erable when the mercury rises in said tube in response to the submersion of said core in said upon the energization of said coil. 3. In a relay, a sealed envelope, a solenoid coil, a pool 0! mercury in said envelope, an annular 7 core within said envelope and floated on said mercury, a tube supported in said envelope having an opening communicating with said pool oi mercury and a restricted vent in the upper end thereof, a pair 01 terminals extending into said'tube and insulated from each other, and a float in said tube normally bridging said terminals and movable out of contact therewith when the mercury rises in said tube in response to the submersion of said core in said mercury upon the energization of said coil.

4. In a relay, a sealed envelope, a solenoid coil surrounding said envelope, a pool of mercury in said envelope, an annular core within said en- 'velope floated on said mercury and within the fleld of said coil, a tube supported in said envelope having an opening communicating with said pool of mercury and a restricted vent in the upper end thereof, a pair of terminals extending into said tube and insulated from each other, and a float in said tube normally bridging said terminals and movable out of contact therewith when the mercury rises in said tube in response to the submersion of said core in said mercury upon the energlzation of said coil.

5. In a relay, a sealed envelope, a solenoid coil, a pool of mercury in said envelope, an annular core within said envelope and floated on said mercury, a tube supported in said envelope having an opening communicating with said pool of mercury. and a restricted vent in the upper end thereof, a pair of terminals extending into said tube and insulated from each other, a float in said tube, and a spring for normally holding said float in bridging engagement with said terminals, said float movable out of engagement with said terminals when the mercury rises in said tube in response to the submersion of said core in said mercury upon the energlzation of said coil.

6. In a relay, a sealed envelope, a solenoid coil, a pool of mercury in said envelope, an annular core within said envelope floated on said mercury,

a tube supported in said envelope, partially submerged in said mercury, having an opening in the wall thereof just above the normal level of said mercury pool and a restricted vent in the upper end thereof, a pair of terminals extending upwardly through the bases of said envelope and tube and insulated from each other, and a float in said tube normally resting on the upper ends of said terminals forming a conducting bridge between them and movable out oi contact therewith when the mercury rises in said tube in response to the submersion of said core in said mercury upon the energization oi said coil.

'7. In a relay, a sealed envelope, a solenoid coil, 8. pool of mercury in said envelope, an annular core within said envelope floated on said mercury, a tube supported in said envelope, partially submerged in said mercury, having an opening in the wall thereof just above the normal level of said mercury pool and a restricted vent in the upper end thereof, a pair of terminals extending downwardly through the upper ends 01' said envelope and tube, and a float in said tube normally out of contact with said terminals and movable into bridging contact therewith when the mercury rises in said tube in response to the submersion of said core in said mercury upon the energisation of said coil.

CLARENCE S. KNOWL'IUN. HOBART M. SPICER. 

